The present invention relates to a color image forming apparatus such as a color electrophotographic copying apparatus for forming a multi-color (two-color or three-color) image or a full-color image and a color recording apparatus constituting an output station of a laser beam printer, a computer, a facsimile machine or the like.
Taking an electrophotographic copying apparatus as an example of a color image forming apparatus, it has been proposed that the apparatus comprises a photosensitive drum functioning as a latent image bearing member and a plurality of developing devices disposed around the photosensitive drum, the developing devices containing different colors of developing agents (U.S. Pat. No. 3,854,449), and that a plurality of the developing devices are supported on a supporting member or turret which is rotatable to revolve the developing devices so that a desired one of them can be moved to oppose the photosensitive drum at a developing station (U.S. Pat. No. 3,987,756).
The latter type is advantageous in that only one of the developing devices is opposed to the image bearing member whereby the peripheral length of the latent image bearing member is minimized.
However, this structure is somewhat disadvantageous in that the maintenance operation and the developer supplying operation tend to be complicated since the plurality of the developing devices are revolvable with the rotation of the supporting member. Therefore, it is desired to provide some means for enabling the operator or a serviceman to supply the correct developers to the developing devices with sure certainty.